Evaluation of four methods for detection of immunoglobulin M antibodies to dengue virus.

Dengue has become hyperendemic in many islands of the Caribbean region. The performance in a diagnostic laboratory of four commercial assays for detection of immunoglobulin M (IgM) antibodies was evaluated. Sera from 62 patients with dengue virus infection were studied. These included 18 patients from whom dengue virus type 2 was isolated in a 1997 outbreak (specimens collected a mean of 14 days after onset of symptoms), 8 patients with dengue hemorrhagic fever (mean time after onset, 11 days), and 36 patients in whom dengue was previously confirmed by serology (mean time after onset, 10 days). Thirty serum specimens from blood donors in a country where dengue is not endemic were used as negative controls. The methods evaluated were two IgM-capture enzyme-linked immunosorbent assays (ELISA) (MRL Diagnostics, Cypress, Calif., and PanBio, Queensland, Australia), a dot ELISA dipstick assay (Integrated Diagnostics, Baltimore, Md.), and a rapid immunochromatographic assay for dengue IgG and IgM (PanBio IC). IgG antibodies were also detected by an ELISA method (MRL Diagnostics). The sensitivities of the four assays were as follows: MRL Diagnostics IgM ELISA, 98.4%; PanBio IgM ELISA, 85.5%; Integrated Diagnostics IgM dot ELISA, 96. 8%; and PanBio IC, 83.9%. The specificities of all tests were 100%. Evidence of secondary dengue was found in all patients with dengue hemorrhagic fever and in 83% of the remaining patients. The MRL Diagnostics IgM ELISA appears to be more sensitive than the PanBio IgM ELISA, and this may be significant when IgM titers are low, particularly in patients with secondary dengue infections. The dot ELISA dipstick assay is equally sensitive and may be more appropriate for use in laboratories with lower workloads.     

Diagnosis of Colorado tick fever virus infection by enzyme immunoassays for immunoglobulin M and G antibodies.

An immunoglobulin M (IgM) capture enzyme immunoassay technique was adapted for the detection of antibody to Colorado tick fever virus in sera from 84 individuals for whom diagnosis had been confirmed by virus isolation or neutralization test. Titers were compared with those for IgG and neutralizing antibodies in these Colorado tick fever cases. IgM antibody titers were higher than neutralizing antibody titers, but neither appeared until 1 to 2 weeks after the onset of illness. Neutralizing antibodies were detected earlier than IgM antibodies, and both were detected with greater frequency than IgG antibodies. Late-convalescent-phase sera contained both neutralizing and IgG antibodies, but IgM was all but undetectable by 2 months after onset. Although the neutralization test may remain the serological test of choice, the enzyme immunoassay for IgM antibody offers a simple and more rapid method of serodiagnosis; the enzyme immunoassay is, however, less sensitive than the neutralization test. Furthermore, because there was a sharp decline in IgM antibody after 45 days, the presence of IgM antibody in a single serum sample provides a basis for the presumptive serodiagnosis of recent Colorado tick fever virus infection.     

Serological markers during dengue 3 primary and secondary infections.

BACKGROUND: The detection of the IgM antibody for the dengue virus in serum by ELISA has become one of the most important and useful methods for diagnosis of dengue using a single acute-phase serum sample. Currently, this system is an invaluable tool for the surveillance of dengue fever (DF) and dengue hemorrhagic fever (DHF). The usefulness of other serological markers such as IgA and IgE have been less studied. OBJECTIVE: To study the IgM, IgA and IgE specific antibody response in dengue 3 infected patients with different clinical picture and type of infection. STUDY DESIGN: One hundred and twenty-seven serum samples collected on days 5-7 at the onset of fever from clinically and serologically confirmed dengue cases were studied. Forty-two were classified as primary dengue fever cases, 48 as secondary dengue fever cases and 37 as secondary dengue hemorrhagic fever cases. All samples were tested by capture ELISA in order to detect dengue IgM, IgA and IgE antibodies. RESULTS AND CONCLUSIONS: In this study, significant differences were observed in the IgM, IgA and IgE response between the study groups. High IgA and IgE OD ratios in secondary dengue cases were found. The usefulness of serotype specific IgM antibody detection is also analyzed and discussed. A priority for future dengue research in terms of protection, recovery of infection and immunopathogenesis is to elucidate the role of these immunoglobulins. The cross reactivity response to IgM between dengue virus serotypes in primary and secondary cases should also be more studied.     

Evaluation of an IgG enzyme-linked immunosorbent assay for dengue diagnosis.

BACKGROUND: The hemagglutination inhibition (HI) test has been one of the standards, with the IgM antibody capture ELISA (MAC-ELISA), for the diagnosis of dengue virus infections. The spread of dengue throughout the world and the increasing number of cases to be tested makes an ELISA-format test for IgG antibodies to replace the HI test highly desirable. OBJECTIVES: Evaluate the use of the IgG-ELISA as a substitute for the HI test in dengue diagnosis. STUDY DESIGN: Paired serum samples defined as being from primary or secondary dengue virus infections by HI, were tested by an ELISA that detects IgG antibodies. The correlations of titers and serologic interpretations between these two tests were examined. RESULTS: The IgG-ELISA showed a low correlation with the HI in primary infections, and a higher correlation in secondary infections because of the influence of IgM antibodies in the HI test. Nevertheless, IgG ELISA titers could be reliably associated with primary or secondary infections when analyzed by days after onset of symptoms, and can be used to characterize the immune response after flavivirus infections. CONCLUSION: The combination of the IgM and IgG ELISAs may be used to serologically diagnose dengue virus infections, since the IgG ELISA can substitute for the HI test in characterizing the immune response to dengue virus infections.     

Reverse ELISA for IgG and IgM antibodies to detect Lassa virus infections in Africa.

BACKGROUND: Anti-Lassa antibodies are detected by indirect immunofluorescence assay (IFA) or by enzyme-immunoassay (ELISA). Both methods have problems to detect low amounts of specific antibodies. OBJECTIVES: We report here highly sensitive and specific reverse ELISAs to detect Lassa virus IgG and IgM antibodies. Due to the reverse techniques, serum samples could be applied at dilutions of 1:10 without increasing non-specific background reactions. STUDY DESIGN: For IgM antibody detection microtiter plates were coated with anti-IgM antibodies and for IgG antibody detection with rheumatoid factor (RF) (Sachers M, Emmerich P, Mohr H, Schmitz H. Simple detection of antibodies to different viruses using rheumatoid factor and enzyme-labelled antigen (ELA). J Virol Methods 1985;10:99-110). In both assays a tissue culture antigen was used in combination with a labeled anti-Lassa monoclonal antibody (Hufert FT, Ludke W, Schmitz H. Epitope mapping of the Lassa virus nucleoprotein using monoclonal anti-nucleocapsid antibodies. Arch Virol 1989;106(3-4):201-12). RESULTS: The reverse ELISA turned out to detect virus-specific IgG and IgM antibody in all 20 samples of West African patients collected 2-8 weeks after onset of Lassa fever. Moreover, both IFA and reverse ELISA found IgG antibodies in 53 out of 643 samples of healthy West Africans (sensitivity of 100%). Six of the 643 samples were positive by reverse IgG ELISA only. Thus, the specificity compared to IIF was 99.0%, but it may be even higher, because compared to IFA the IgG ELISA was clearly more sensitive in detecting low antibody titers. CONCLUSIONS: In Ghana 3% seropositives were found by IFA, but 4% by the reverse ELISA. The reverse ELISAs can be performed with high sensitivity and specificity under field conditions in Africa.     

用重组汉坦病毒NP、GP检测急性期HFRS患者血清中特异性IgG、IgM、IgA抗体

目的 探讨肾综合征出血热(HFRS)患者急性期IgA、IgG、IgM抗体的变化规律。方法 使用套式RT-PCR检测此次病毒感染情况。用杆状病毒表达的汉坦病毒重组核蛋白(rNP)和糖蛋白(rGP)为抗原，使用ELISA方法检测了14例急性期肾综合征出血热患者的6l份系列血清中的IgA、IgG、IgM抗体。结果 14例肾综合征出血热患者中，ll例患者的血清用RT-PCR检出家鼠型汉坦病毒核酸。几乎所有肾综合征出血热患者早期即有IgA、IgM、IgG抗体的迅速升高，抗rNP抗体滴度明显高于rGP。3种抗rNP抗体中早期IgG上升趋势最为显著，IgM与IgA次之，IgM与IgA上升趋势相近，但IgA的滴度明显高于IgM。抗rGP抗体中XgA变化最显著，IgG次之。IgM发病2周内总的变化趋势不明显，但是发病l周内滴度上升趋势明显，而发病第2周内则呈下降趋势。其中l例RT-PCR阳性的患者，早期IgM未测出，IgA的滴度却较高。l例重度患者，抗糖蛋白IgG、IgM和IgA抗体滴度均低于其他患者，且整个急性期一直维持较低水平。结论 肾综合征出血热急性期IgA、IgG、lgM变化具有明显的规律，抗糖蛋白和核蛋白抗体病患规律不同，检测IgM的同时检测IgA，可以提高诊断的准确性。     

Evaluation of Four Methods for Detection of Immunoglobulin M Antibodies to Dengue Virus

Dengue has become hyperendemic in many islands of the Caribbean region. The performance in a diagnostic laboratory of four commercial assays for detection of immunoglobulin M (IgM) antibodies was evaluated. Sera from 62 patients with dengue virus infection were studied. These included 18 patients from whom dengue virus type 2 was isolated in a 1997 outbreak (specimens collected a mean of 14 days after onset of symptoms), 8 patients with dengue hemorrhagic fever (mean time after onset, 11 days), and 36 patients in whom dengue was previously confirmed by serology (mean time after onset, 10 days). Thirty serum specimens from blood donors in a country where dengue is not endemic were used as negative controls. The methods evaluated were two IgM-capture enzyme-linked immunosorbent assays (ELISA) (MRL Diagnostics, Cypress, Calif., and PanBio, Queensland, Australia), a dot ELISA dipstick assay (Integrated Diagnostics, Baltimore, Md.), and a rapid immunochromatographic assay for dengue IgG and IgM (PanBio IC). IgG antibodies were also detected by an ELISA method (MRL Diagnostics). The sensitivities of the four assays were as follows: MRL Diagnostics IgM ELISA, 98.4%; PanBio IgM ELISA, 85.5%; Integrated Diagnostics IgM dot ELISA, 96.8%; and PanBio IC, 83.9%. The specificities of all tests were 100%. Evidence of secondary dengue was found in all patients with dengue hemorrhagic fever and in 83% of the remaining patients. The MRL Diagnostics IgM ELISA appears to be more sensitive than the PanBio IgM ELISA, and this may be significant when IgM titers are low, particularly in patients with secondary dengue infections. The dot ELISA dipstick assay is equally sensitive and may be more appropriate for use in laboratories with lower workloads.     

Dengue NS1-specific antibody responses: isotype distribution and serotyping in patients with Dengue fever and Dengue hemorrhagic fever

To understand the antibody responses to dengue (DEN) nonstructural 1 (NS1) glycoprotein and their roles in protective immunity or pathogenesis of dengue fever (DF) and dengue hemorrhagic fever (DHF), we have analyzed the NS1-speccific IgM, IgA and IgG antibodies from patients with DF and DHF. An isotype-specific, indirect enzyme-linked immunosorbent assay (ELISA) was established by coating a NS1-specific monoclonal antibody (MAb), D2/8-1, to capture soluble NS1 antigens secreted in the culture supernatants of Vero cells infected with DEN virus. We observed strong anti-NS1 antibody responses in all of the convalescent sera of patients with DF and DHF. Similar NS1-specific isotypic and serotypic antibody responses were found in the sera from DF and DHF patients. The results showed that all DEN infections induced significant NS1-specific IgG, whereas 75% and 60% of primary DF patients vs. 40% and 90% of secondary DF patients produced IgM and IgA antibodies, respectively. Specificity analysis showed that DEN NS1-specific IgG and IgA antibodies cross-react strongly to Japanese encephalitis (JE) virus NS1 glycoprotein, whereas DEN NS1-specific IgM antibodies do not cross-react to JE virus NS1 glycoprotein at all. The serotype specificity of NS1-specific IgM, IgA and IgG were found to be 80%, 67% and 75% for primary infections, and 50%, 22% and 30% for secondary infections in positive samples of DF patients. Similar pattern was found in DHF patients. The results showed that all of the DF and DHF patients produced significant NS1-specific antibodies. We did not observe direct correlation between the anti-NS1 antibody responses and DHF because sera from patients with DF and DHF showed similar anti-NS1 antibody responses.     

Evaluation of six commercial point-of-care tests for diagnosis of acute dengue infections: the need for combining NS1 antigen and IgM/IgG antibody detection to achieve acceptable levels of accuracy

Six assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.     

Immunoglobulins M and G to varicella-zoster virus measured by solid-phase radioimmunoassay: antibody responses to varicella and herpes zoster infections.

Both immunoglobulin M (IgM) and IgG antibodies to varicella-zoster virus (VZV) were detectable in a solid-phase radioimmunoassay with 125I-labeled goat antisera to human immunoglobulins. Primary infection with VZV was associated with early production of IgM and IgG antibodies and rapid development of lymphocyte transformation to VZV antigen. Among eight subjects with varicella tested 1 to 4 days after onset, seven patients had IgG and six patients had IgM antibodies; all patients had both IgG and IgM antibodies within 7 days. An IgM response was documented by radioimmunoassay in 18 of 26 patients with herpes zoster. VZV antibodies could be assayed by radioimmunoassay in unfractionated serum with commercial goat antisera to human immunoglobulins and commercial VZV antigen. VZV-specific IgG binding was present in all sera from 42 subjects with a VZB antibody titer of greater than or equal to 1:8 as determined by indirect immunofluorescence and cellular immunity to VZV as determined by lymphocyte transformation and who had had varicella at least 20 years before testing. The geometric mean titer was 1:6,309, and titers were greater than or equal to 1:16,384 in 20 subjects. Antibody was present as determined by radioimmunoassay in 14 samples negative by complement fixation and in five samples negative by complement fixation and immune adherence hemagglutination. No specific binding was observed in 21 sera from subjects who were not immune to VZV as determined by indirect immunofluorescence or lymphocyte transformation despite the presence of herpes simplex or cytomegalovirus antibody indicated by complement fixation in 15 sera. High titers of VZV IgM antibody were detected in unfractionated sera despite the presence of high titers of VZV IgG antibody. The VZV radioimmunoassay provided a sensitive and practical method for measuring VZV IgG and IgM antibodies.     

Comparison of two rapid diagnostic assays for detection of immunoglobulin M antibodies to dengue virus

Two easy-to-use commercial diagnostic assays, a dipstick enzyme-linked immunosorbent assay (ELISA) (Integrated Diagnostics, Baltimore, Md.) and an immunochromatographic card assay (PanBio, Brisbane, Australia) were evaluated for detection of immunoglobulin M (IgM) antibody to dengue virus with an in-house IgM antibody capture microplate ELISA as a reference assay. The dipstick ELISA was based on the indirect-ELISA format using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human IgM antibody as the detector. The total assay time was 75 min. The immunochromatographic card assay was based on the antibody capture format and separately measured both anti-dengue virus IgM and IgG in the same test. Colloidal-gold-labeled anti-dengue virus monoclonal antibody bound with dengue virus 1 to 4 antigen cocktail was the detector, and anti-human IgM and IgG were the capture antibodies. The total assay time was <10 min. Sera from 164 individuals classified as either anti-dengue virus IgM positive (94) or anti-dengue virus IgM negative (70) in the reference microplate ELISA with a dengue virus 1 to 4 antigen cocktail were tested in the two commercial assays. The dipstick ELISA missed 7 of 94 positive samples, for a sensitivity of 92.6%, while the immunochromatographic card assay missed two positive samples, for a sensitivity of 97.9%. Of the 70 negative samples, four were false positive by the dipstick ELISA and two were false positive in the immunochromatographic card assay, resulting in specificities of 94.3 and 97.1%, respectively. Both commercial assays provide sensitive and specific detection of anti-dengue virus IgM antibody and could prove useful in settings where the microplate ELISA is impractical.     

Relevance of detection of immunoglobulin M antibody response in birds used for arbovirus surveillance.

Young chickens were inoculated with 5,000 PFU of eastern equine encephalitis (EEE) virus and bled at intervals thereafter for determinations of hemagglutination-inhibiting (HI), neutralizing (N), immunoglobulin M (IgM), and IgG antibodies. HI, N, and IgM antibodies were first detected 4 days after infection, and IgG was detected 7 days after infection. All four antibodies persisted through day 90 after infection. HI, N, and IgM antibody titers remained elevated and were not cross-reactive with the related alphavirus western equine encephalitis (WEE) virus. IgG antibody titers also remained high, but heterologous reactivity to WEE virus increased with time after infection. Serum samples from sentinel chickens and wild birds infected in nature with EEE, WEE, or St. Louis encephalitis virus and submitted to this laboratory from state and local health departments were tested for IgM antibody by using anti-chicken IgM for capture and for IgG antibodies to the EEE and WEE viruses. There was essentially complete correlation between HI, N, and either IgM (indicating recent infections) or IgG (indicating more remote infections) antibody. We conclude that the IgM antibody capture enzyme immunoassay can be used as a specific and sensitive assay to replace the routinely used HI test for detecting antibody in sentinel chickens and in young, wild birds used for arbovirus surveillance. The test is rapid and relatively inexpensive and can be performed in essentially all adequately supplied laboratories.     

Simultaneous detection of immunoglobulin A (IgA) and IgM antibodies against hepatitis E virus (HEV) Is highly specific for diagnosis of acute HEV infection

Serum samples collected from 68 patients (age, mean +/- the standard deviation [SD], 56.3 +/- 12.8 years) at admission who were subsequently molecularly diagnosed as having hepatitis E and from 2,781 individuals who were assumed not to have been recently infected with hepatitis E virus (HEV; negative controls; 52.9 +/- 18.9 years), were tested for immunoglobulin M (IgM) and IgA classes of antibodies to HEV (anti-HEV) by in-house solid-phase enzyme immunoassay with recombinant open reading frame 2 protein expressed in the pupae of silkworm as the antigen probe. The 68 patients with hepatitis E had both anti-HEV IgM and anti-HEV IgA. Among the 2,781 controls, 16 (0.6%) had anti-HEV IgM alone and 4 (0.1%) had anti-HEV IgA alone: these IgA/IgM anti-HEV-positive individuals were not only negative for HEV RNA but lack IgG anti-HEV antibody as well (at least in most of the cases). Periodic serum samples obtained from 15 patients with hepatitis E were tested for HEV RNA, anti-HEV IgM, and anti-HEV IgA. Although HEV RNA was detectable in the serum until 7 to 40 (21.4 +/- 9.7) days after disease onset, both IgM and IgA anti-HEV antibodies were detectable until 37, 55, or 62 days after disease onset in three patients and up through the end of the observation period (50 to 144 days) in 12 patients. These results indicate that detection of anti-HEV IgA alone or along with anti-HEV IgM is useful for serological diagnosis of hepatitis E with increased specificity and longer duration of positivity than that by RNA detection.     

阳江市一起基孔肯雅热暴发疫情流行病学调查

目的了解基孔肯雅热的流行特征,探索有效的防控策略,为今后防控工作提供依据。方法根据病例定义进行病例搜索,对符合病例定义的病例进行流行病学调查;采用酶联免疫吸附试验方法检测登革热病毒IgM和IgG抗体;采用实时荧光定量逆转录聚合酶链反应方法检测登革热病毒核酸和基孔肯雅热病毒核酸。结果 2010年9月12日至10月21日,阳江市某建筑工地发生基孔肯雅热病27例,总罹患率为11.07%（27/244）;其中男性17例,占62.96%,女性10例,占37.04%;检测15份恢复期病例血样登革热病毒IgM和IgG抗体,其中2份病例血样IgM抗体阳性,其余13份为阴性,15份病例血样IgG抗体均为阴性;检测5份现症病例血样,登革热病毒核酸均为阴性,2份基孔肯雅热病毒核酸阳性。结论这是一起基孔肯雅热暴发疫情,加强出入境检疫、开展医疗机构症状监测和控制传播疾病的媒介密度是预防控制孔肯雅热的重要措施。     

Early Diagnosis and Treatment of Patients with Symptomatic Acute Q Fever Do Not Prohibit IgG Antibody Responses to Coxiella burnetii

Little is known about the effect of timing of antibiotic treatment on development of IgG antibodies following acute Q fever. We studied IgG antibody responses in symptomatic patients diagnosed either before or during development of the serologic response to Coxiella burnetii. Between 15 and 31 May 2009, 186 patients presented with acute Q fever, of which 181 were included in this retrospective study: 91 early-diagnosed (ED) acute Q fever patients, defined as negative IgM phase II enzyme-linked immunosorbent assay (ELISA) and positive PCR, and 90 late-diagnosed (LD) acute Q fever patients, defined as positive/dubious IgM phase II ELISA and positive immunofluorescence assay (IFA). Follow-up serology at 3, 6, and 12 months was performed using IFA (IgG phase I and II). High IgG antibody titers were defined as IgG phase II titers of ≥1:1,024 together with IgG phase I titers of ≥1:256. At 12 months, 28.6% of ED patients and 19.5% of LD patients had high IgG antibody titers (P = 0.17). No statistically significant differences were found in frequencies of IgG phase I and IgG phase II antibody titers at all follow-up appointments for adequately and inadequately treated patients overall, as well as for ED and LD patients analyzed separately. Additionally, no significant difference was found in frequencies of high antibody titers and between early (treatment started within 7 days after seeking medical attention) and late timing of treatment. This study indicates that early diagnosis and antibiotic treatment of acute Q fever do not prohibit development of the IgG antibody response.     

Association of platelet count and serological markers of dengue infection- importance of NS1 antigen

Introduction: Dengue is an acute viral infection with potential fatal complications. Specific antibody detection has been the mainstay of diagnosis which is prone for both false positive and false negative reactions. The newer parameter NS1 appears to be highly specific and reliable for diagnosis of dengue infection from the first day of fever. Platelet count is the only accessory test for diagnosis of dengue infection in the peripheral laboratories. Therefore, we tried to evaluate the association of platelet counts against NS1 and IgM/IgG in dengue infections. Materials and Methods: Serum samples from clinically suspected dengue cases were tested for NS1, IgM and IgG by immunochromatography-based test. Platelet counts were obtained for all positive cases and 150 dengue seronegative cases of fever that served as controls. Test results of dengue-specific parameters were compared against platelet counts. The proportions obtained were compared by Standard error of the difference between the proportions (SEP test). Results: Of 2104 samples tested, 320 were positive for one or more dengue parameters. Of the 320, 95 were positive for NS1 only, 161 showed IgM only while 9 showed IgG only. More than one marker was detected in the remaining 55 samples. Thrombocytopenia was more consistently associated whenever NS1 was detected compared to antibody detection (P value <0.001). Conclusions: Inclusion of NS1 in the diagnosis of dengue increases the detection rate significantly. In cases of fever, thrombocytopenia is more consistently found in dengue positive rather than dengue negative subjects. It correlates well when NS1 and IgM are detected simultaneously.     

Detection of antibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assay.

Acute-phase serum from a patient with aplastic crisis provided sufficient human parvovirus B19 to make a monoclonal antibody against B19 and to develop antigen and immunoglobulin M (IgM) and IgG antibody detection enzyme-linked immunosorbent assays (ELISAs). The indirect capture antibody method was used for all three assays. Antigen was detected in 8 of 29 sera drawn within 2 days of onset of illness from patients with aplastic crisis. These sera had high titers of virus by electron microscopy and DNA hybridization and had no detectable B19 antibody. Antigen was not detected in serum specimens that had low titers of B19 DNA and had B19 antibody. With the IgM ELISA, we detected B19 IgM in over 85% of clinical cases of aplastic crisis and fifth disease and less than 2% of controls. The prevalence of B19 IgG antibodies increased with age. Approximately 2% of children less than 5 years of age and 49% of adults greater than 20 years of age had B19 IgG antibodies. The B19 antibody ELISAs are sensitive and specific tests to detect B19 infections.